An Oklahoma man was arrested on federal charges for allegedly threatening to kill police and FBI agents.

Court documents said Dustin McCaskill ran two anti-police Facebook pages that News 9 has reported on in the past.

McCaskill was arrested on federal charges of interstate communications with intent to extort.

Court documents said the Ardmore native, who now lives in Colorado, runs sites called 'Southern Oklahoma Cop Block' and 'Colorado Cop Block.'

McCaskill allegedly posted comments online that were so alarming, one police department in Colorado warned its officers to be careful if they ever ran into him.

Agents said McCaskill posted a black police officer's photo on the Oklahoma page and the officer's home address, with the caption, "Can we get a rope wrapped around the black cop's neck? He needs to be executed."

“Any threat, you've got to consider viable so you can check it out and make sure,” said John George, President of Oklahoma City's Fraternal Order of Police. “Unfortunately, our officers out here every day are kind of sitting ducks sometimes, they can be targets,” George added.

Another post accompanied by a picture read, “I'm going to advocate the death of police ... If someone was to gun this Oklahoma officer down, I will be the first to donate to his defense fund."

FBI agents said they warned McCaskill about his posts in December and they arrested him in Las Vegas on Jan. 15 when new posts surfaced, like, "I'm going to kill an officer or 2" and "I'm threatening to kill a cop or FBI agent" as well as "Maybe it's time for these police officers families to suffer, too."

The affidavit said McCaskill told agents he hopes his words inspire others.

George said that factor is equally scary.

“It's the people that may be reading it, we've got a lot of mentally unstable people out there, that may unfortunately give them the idea to go out and do something or act on one of these guy's threats,” George explained.

A Nevada Cop Block page reported this month the organization is trying to disassociate itself with McCaskill.

“They live their life around just trying to disrupt what we do and you know we got a hard job, our officers do the best job they can, we make mistakes sometimes,” George told News 9.

According to the affidavit, McCaskill's mother sent an email to police about her son that said, "I'm not sure if he's safe to ever be in the general public."

Police said if you ever see threatening comments online, you should report it so they can investigate.

Often times they don't know about a threat until it's reported.

The information in this news story was provided by law enforcement with the request News 9 inform the public of, and/or assist in locating a person in connection with, a police investigation. News 9 is cooperating with authorities by informing, and/or seeking the assistance of, the public in this investigation. The information and the photographs or video in this news story was provided by law enforcement and News 9 can make no independent verification of the accuracy of the information provided to it in this request by police or other law enforcement agencies.